The Oklahoma Sooners head into 2011 trying to fill a massive void at the running back position. Demarco Murray and Mossis Madu are no longer a part of the OU football program. Those two running backs accounted for over 70 percent of the Sooners' rushing yards in 2010.

That leaves running backs coach Cale Gundy with a lot of production to replace, and even though he has plenty of talented youngsters, the experience is lacking.

It's not unfamiliar territory for Gundy, who was forced to press true freshmen Quentin Griffin into service in 1999 and freshman Adrian Peterson in 2004.

Peterson had one of the best freshmen seasons in college football history, and Griffin ended up leading Oklahoma to a national championship as the starting running back the next season.

So even though Gundy's oldest running back this spring is third-year sophomore Jonathan Miller, he should have no problems working that magic again, right?

"I think it's a little different," said Gundy, who heads into his 13th season with the Sooners. "When Quentin played we were very simple in what we did in the passing game and in the runs, we didn't have very many. We're a little bit more multiple in the things we do right now.

"As a matter of fact it would have been different on A.D. because back then we still huddled up and we don't huddle anymore."

Oklahoma's offense has become much more complicated for young running backs with the advent of the up-tempo no-huddle approach started by Kevin Wilson, and now continued by co-offensive coordinators Josh Heupel and Jay Norvell.

"It's sign language," explained Gundy of OU's offensive system. "You've got to understand, you've got to communicate, you've got to talk. You're not in the huddle and you don't have a quarterback who is telling everybody what the play is. You don't have time to slowly walk up to the line of scrimmage."

There's also the added responsibilities of picking up blitzing linebackers and defensive backs, as well as everything that's involved in the passing game.

That's something Gundy never had to worry about the last two years with Murray in the backfield.

"When you have a Demarco and you have a Mossis Madu that have been around here for four or five years - all of a sudden you have a bunch of young guys out here who are capable of doing it, who know what they're supposed to do, but haven't had the reps and the plays that those guys had that made them successful," said Gundy. "Those are the things you have to keep working through."

Gundy says that each running back is getting 25 to 30 live reps through the first eight practices of spring football. But they're also standing on the sidelines taking mental reps, which are important.

Finch is also limited as he recovers from a stress fracture he suffered late in the 2010 season, even though he is able to practice full speed from time-to-time.

But right now, finding a young back that can handle multiple responsibilities is a luxury Gundy and the Oklahoma offense doesn't have.

Although it would appear Miller is one player who is earning Gundy's trust halfway through spring practices.

"He's been here for two years," said Gundy of Miller. "He's watched a lot of film and Jonathan is a smart young man. Jonathan is somebody that I know if we had to play tomorrow, I could count on Jonathan to know what he has to do besides just getting the ball in his hand. He knows our system and he's learning and he's almost one of those guys that's there in knowing what he's supposed to be doing."

Nothing has been settled at this point. It's likely that these youngsters will head into the fall spending plenty of time studying film. Long nights studying the playbooks won't hurt their cases for playing time either.

Even true freshmen Brandon Williams is showing Gundy enough encouraging moments to make him believe he can be a factor heading into next season.

"I've been really surprised at how quick he's been able to adapt because our system is complicated. It is all hand signals and we do a bunch," said Gundy. "There's a lot of responsibilities, but he is really learning the concepts of the pass plays and understanding pass protection.

"The more reps he gets, he's going to be better at it. He's made good progress in the eight practices we've had. Is he there? No. But he's probably made more progress than I thought he would."

Gundy has been here before. It just happens that time and progress have made this go-around more complicated than previous years.

And just as Gundy sees progress, he also expects regression. That's usually the signature of having a lot of youth at the position. And something Gundy witnessed first hand during the first major scrimmage last weekend.

"Sometimes we've got some talent that can overcome some youth and maybe some mistakes and shine in some areas," Gundy said. "We did some good things down on the goal line. We're learning as an offense to be more physical but as soon as I say that we'll go out in the next scrimmage and the defense will completely shut us down. I know how it goes."